Practice Questions

  1. Home
  2. Free Resources
  3. Practice Questions
  4. 5986
TLS Online TPP Program

#Question id: 7186

In dictyostelium stalk and spore cell maturation depends on cAMP level. Which of the following statement is incorrect regarding to this process?

#Unit 5. Developmental Biology
  1. During spore formation, ACG localizes to the spore surface when the prespore vesicles fuse with the plasma membrane. The cAMP phosphodiesterase RegA also plays a crucial role in regulating intracellular cAMP levels.
  2. This process is mediated by socalled sensor histidine kinases/phosphatases which either phosphorylate or dephosphorylate themselves on a histidine residue when a signal molecule binds to their sensor domain.
  3. Ammonia inhibits the onset of fruiting body formation and stalk maturation, activates the histidine phosphatase activity of sensor histidine phophatase C (DhkC), resulting in RegA activation, hydrolysis of cAMP and inhibition of PKA activity.
  4. Spore differentiation factor 2 (SDF-2) activates the histidine phosphatase activity of DhkA (histidine phosphatase A), which results in the inactivation of RegA, the accumulation of cAMP and in PKA activation, which subsequently causes spore maturation.
More Questions
TLS Online TPP Program

#Question id: 10653

#Unit 10. Ecological Principles

All offspring are produced in a single reproductive event, we term this pattern semelparity. Which of the following is characteristics feature for semelparity individuals?

a) Semelparity is common in insects and other invertebrates

b) Semelparous organisms may live for many years before reproducing

c) semelparity occur only in plant

d) In semelparity, exploitation competition is more common than interference competition
TLS Online TPP Program

#Question id: 9593

#Unit 6. System Physiology – Plant

The lower-energy orbital of the positively charged oxidized reaction centre chlorophyll has a vacancy and can accept an electron If the acceptor molecule donates its electron back to the reaction centre chlorophyll, What will happened?
TLS Online TPP Program

#Question id: 3339

#Unit 11. Evolution and Behavior

In a plant species, flower color locus either homozygous or heterozygous with genotype RR-red, Rr- pink and rr- white. The Proportional of pink flower in generation 0 is .50.  What is the level of remaining pink flower in a third generation of repeated selfing? 
TLS Online TPP Program

#Question id: 33526

#Unit 2. Cellular Organization

The number of protein-coding genes is less than the number of potential polypeptides that can result in several polypeptides from the same gene because of mechanisms 
A. alternative splicing
B. alternate promoter selection, 
C. alternate poly(A) site selection
D. Number of Introns in the gene
TLS Online TPP Program

#Question id: 3808

#Unit 3. Fundamental Processes

Fibroblast cells from several different xeroderma pigmentosa patients were cultured, then fused in intergenic complementation studies. Which cell fusions would not result in a hybrid capable of repairing damaged DNA?